Neural and psychological mechanisms of selective attention under load. (360G-Wellcome-080568_Z_06_Z)

Load theory has resolved the fundamental debate in attention research on the extent to which attention can prevent distraction by irrelevant stimuli and has stimulated much behavioural and neuroimaging research over the last decade. The next challenge is to achieve better understanding of the underlying mechanisms by which load on different brain functions (perception, working memory) affect the ability to focus attention on a task whilst ignoring task-irrelevant stimuli. Specifically, our key g oals are: 1) To establish the effects of the level and type of load on perceptual sensitivity as behaviourally assessed with d prime. 2) To test with functional imaging a neural base-line shift account for the effects of load. 3) To examine the effects of load on visual cortex excitability, as assessed with the intensity of the trasncranial magnetic stimulation needed to trigger phosphene perception. 4) To test the distinction between active versus passive control of attention by load using beh avioural and neuroimaging techniques. The research proposed would provide better understanding of the mechanisms by which focused attention prevents being distracted by goal-irrelevant stimuli as well as clearer conception of the role for executive functions such as working memory in control of focused visual attention.